The constantly increasing demands of users have stimulated the rapid development of mobile communication technologies. Currently, 5G mmWave (millimeter-wave) networks are actively being developed. 5G mmWave networks may require higher performance due to user experience requirements, including such factors as ease of connectivity with nearby devices and improved energy efficiency. Millimeter-wave technologies encounter a variety of fundamental challenges, which are associated with the physics of antenna arrays, the structure of a high-speed transceiver, etc.
The basic challenges and constraints affecting current radio-frequency (RF) signal transmission/reception devices (switches, phase shifters, antennas) with operating frequencies over 5 GHz are as follows:
1) high losses encountered in the use of standard semiconductor technologies, which results in low energy efficiency;
2) off-the-shelf components and circuits having low parasitic characteristics are sophisticated or large and have a high cost.
Previously, the use of known photoconductive elements in high-frequency signal transmission/reception devices at these frequencies has been impractical because of the inherent disadvantages thereof:
1) high losses;
2) large amount of power required for control;
3) large surface area required for irradiation.
For example, the following high-frequency switching devices using optical elements are known.
U.S. Pat. No. 7,965,249 B1, Jun. 21, 2011, “Reconfigurable radio frequency (RF) surface with optical bias for RF antenna and RF circuit applications”, Rockwell Collins.
This document discloses a reconfigurable radio-frequency surface with optical bias for application in RF antennas and RF circuits. The surface is a multicell structure (grid) of metallic squares connected by photoconductive compounds. This structure controls antennas (by frequency or polarization).
The disadvantage of this solution is a great number of photoconductive pixels needed in order for the device to provide acceptable scan characteristics.
US 2015/349418, Mar. 12, 2015, “Wide band reconfigurable planar antenna with omnidirectional and directional radiation patterns”, UNIV DREXEL [US], ADANT TECHNOLOGIES INC [US].
The document discloses a wide-band reconfigurable planar antenna with omnidirectional and directional radiation patterns, in which switching is performed between dipoles at a feed point.